Update Ciphers comment

.ssh/config

@@ -57,6 +57,11 @@ Host *
     #   not encrypt message sizes when GCM (or EtM) is in use. 
     #   This allows some traffic analysis even without decrypting the data.
     #   See: http://blog.djm.net.au/2013/11/chacha20-and-poly1305-in-openssh.html
+    # [email protected] offers both encryption and authentication. 
+    #  As such, no separate MAC is required. If the [email protected] 
+    #  cipher is selected in key exchange the offered MAC algorithms are ignored 
+    #  and no MAC is required to be negotiated.
+    #  See: https://github.com/openssh/openssh-portable/blob/V_8_2/PROTOCOL.chacha20poly1305
 
     MACs [email protected],[email protected],[email protected]
     # Only use encrypt then mac (etm) MACs